Sentence examples for are two main difficulties from inspiring English sources

However, there are two (main) difficulties in this study.

There are two main difficulties in doing this.

There are two main difficulties with this way of drawing the line.

There are two main difficulties in neuropharmacology: drugs have to pass the blood brain barrier and then to be internalized by targeted cells.

There are three main difficulties to achieve this task: (1) how to quantify molecular structure; (2) identify which are the relevant structural descriptors (or structure derived) that are the most adequate for the problem at hand; and (3) how to actually map the descriptors selected to the property being modeled [20 22, 56, 57].

There are three main difficulties.

But there were two main difficulties.

There appear to be two main difficulties with this view.

There have been three main difficulties that we have overcome with some assumptions and left their discussions to further studies.

There are two main ones.

There are two main criticisms.